Donald Trump suggests Florida shooter was 'mentally disturbed', just moments after suspect charged over massacre

'Must always report such instances to authorities, again and again!', tweets US President

Donald Trump has waded into the aftermath of the Florida school shooting with a tweet suggesting suspect Nikolas Cruz was “mentally disturbed”, just moments after the teenager was charged.

The US President tweeted: “So many signs that the Florida shooter was mentally disturbed, even expelled from school for bad and erratic behaviour. Neighbours and classmates knew he was a big problem. Must always report such instances to authorities, again and again!”

Cruz has been charged with the premeditated murder of 17 people at a school in Florida.

Police say the 19-year-old was behind Wednesday’s shooting at Marjory Stoneman Douglas High School in Parkland.

A further 14 people were wounded and taken to hospital following the attack in which Cruz allegedly targeted students and staff with an AR-15 semi-automatic rifle.

He was also said to have been equipped with a gas mask, smoke grenades and a large amount of additional ammunition.

It was the nation's deadliest school shooting since a gunman attacked an elementary school in Newtown, Connecticut, more than five years ago.

Mr Trump’s tweet contrasted with the measured tone of his earlier message of condolence to victims.

“My prayers and condolences to the families of the victims of the terrible Florida shooting. No child, teacher or anyone else should ever feel unsafe in an American school”, he tweeted on Wednesday.

Cruz, whose social media posts about guns and knives have been described by police as “very disturbing”, was arrested about two miles away after he fled the scene of the massacre.

Authorities offered no immediate details about Cruz or his possible motive, except to say that he had been expelled from the high school, which has about 3,000 students.

Students who knew him described a volatile teenager whose strange behaviour had caused others to end friendships with him.

Cruz was booked into the Broward County Jail early on Thursday, still wearing the hospital gown he was given after being treated for laboured breathing following his arrest.

He was later questioned overnight before being taken to jail.

Additional reporting by agencies